JNCIS-ENT Practice Test 9 — 10 Questions

Question 1

You are configuring a Link Aggregation Group (LAG) on an EX series switch. Which statement is correct regarding LACP active mode?

Accepted Answer

The interface will actively transmit LACP packets to initiate and negotiate the aggregation with the peer device.. In LACP active mode, the interface actively transmits LACP packets to the remote peer to negotiate the link aggregation.

Answer

The interface will only respond to LACP packets and never transmit them.

Answer

Active mode can only be used when connecting Juniper switches to non-Juniper servers.

Answer

LACP active mode requires static pinning of member links and disables dynamic hash selection.

Question 2

Which of the following is required for two routers to form a Level 2 adjacency?

Accepted Answer

Matching Level 2 support.. For two routers to form a Level 2 adjacency in IS-IS, both must be configured to support Level 2 routing. This is achieved by configuring the interfaces with 'level 2' or 'level 1-2' (the default). If one router is configured as Level 1 only, it will not form a Level 2 adjacency with a Level 2-capable router. The other options are not required: hostnames can differ, area addresses only need to match for Level 1 adjacencies, and System IDs must be unique, not identical.

Answer

Identical hostname configurations.

Answer

Matching Area Addresses.

Answer

Identical System IDs.

Question 3

When configuring Filter-Based Forwarding (FBF), which THREE components are absolutely mandatory for successful operation? (Choose three)

Accepted Answer

A firewall filter with 'then routing-instance ' action.. Option A is correct because FBF requires a firewall filter that matches traffic and uses the 'then routing-instance ' action to redirect matching packets into the alternate routing table. Option B is correct because that action must reference a routing instance of type 'forwarding' (or 'virtual-router'), which provides the separate routing table where the redirected traffic is resolved. Option C is correct because the filter must be applied as an input filter on the ingress interface so that packets are classified and redirected before the normal destination lookup occurs. Option D is incorrect because BGP multipath is a load-balancing feature and is not required for FBF to function. Option E is incorrect because RSVP-TE LSPs are an MPLS traffic-engineering mechanism and are unrelated to the mandatory FBF configuration components.

Answer

BGP multipath enabled across all core interfaces.

Answer

An RSVP-TE LSP tunnel configured between the routers.

Question 4

Which CLI command displays the packet statistics, errors, and drop counters for a Link Aggregation Group (LAG) named ae0?

Accepted Answer

show interfaces ae0. The 'show interfaces ae0' command displays general interface statistics, error counts, and drops for the aggregated interface.

Answer

show chassis interface-drops ae0

Answer

show virtual-chassis interface ae0

Answer

show lacp statistics ae0

Question 5

When configuring a GRE tunnel source and destination address on a Junos device, which configuration hierarchy is used?

Accepted Answer

set interfaces gr-0/0/0 unit 0 tunnel source destination . On Junos, GRE tunnel source and destination addresses are configured under the tunnel interface unit hierarchy using 'set interfaces gr-0/0/0 unit 0 tunnel source destination '. This is the standard syntax for GRE tunnels, where the tunnel interface is a gr- interface and parameters are applied at the unit level.

Answer

set routing-options tunnels source destination

Answer

set protocols gre source destination

Answer

set system tunnel source destination

Question 6

You are configuring OSPF on a Junos device and need to ensure that the router prefers internal OSPF intra-area paths over inter-area paths, and inter-area paths over external paths. According to OSPF route preference rules, what is the evaluation order?

Accepted Answer

Intra-area > Inter-area > External Type 1 > External Type 2. OSPF route preference follows a strict order: intra-area (O) routes are most preferred, then inter-area (O IA), then external Type 1 (E1), and finally external Type 2 (E2). This order is based on the OSPF path selection algorithm, where routes within the same area are considered most reliable and external routes least.

Answer

Inter-area > Intra-area > External Type 2 > External Type 1

Answer

External Type 1 > Intra-area > Inter-area > External Type 2

Answer

External Type 2 > External Type 1 > Inter-area > Intra-area

Question 7

Which command displays the IS-IS interface parameters?

Accepted Answer

show isis interface. 'show isis interface' shows the configuration and state of IS-IS interfaces.

Answer

show isis configuration

Answer

show interfaces isis

Answer

show protocols isis interface

Question 8

Which THREE parameters are included when calculating the MST region configuration digest? (Choose three.)

Accepted Answer

VLAN-to-instance mapping table. The MST region configuration digest is an MD5 hash computed over the region's configuration attributes, and it includes the VLAN-to-instance mapping table (A), the configuration name (B), and the revision number (E) — these three define the region's identity and ensure all switches agree on the same MST region. The VLAN-to-instance mapping (A) determines which VLANs belong to which MST instances, the configuration name (B) is the alphanumeric region identifier, and the revision number (E) is the 16-bit value that must match across all switches in the region. The root bridge MAC address (C) and bridge priority value (D) are not part of the digest; they are per-instance spanning-tree parameters used for root election and topology calculation, not region configuration attributes.

Answer

Root bridge MAC address

Answer

Bridge priority value

Question 9

An administrator needs to configure an OSPF stub area on a Juniper router. Which THREE characteristics apply to a standard OSPF stub area? (Choose three.)

Accepted Answer

The ABR injects a default route (0.0.0.0/0) into the area. In a standard OSPF stub area, the ABR blocks Type 5 AS-external LSAs from being flooded into the area (option C), which is the defining restriction that keeps external routing information out of the stub. To still provide reachability to external destinations, the ABR injects a default route (0.0.0.0/0) into the stub area via a Type 3 summary LSA (option B), so internal routers can forward traffic toward the ABR. Because Type 5 LSAs are blocked and external connectivity depends on that default route, ASBRs cannot reside inside a stub area, and virtual links cannot transit a stub area (option D) since a virtual link requires the transit area to carry Type 5 LSAs and cannot be configured through a stub. Option A is incorrect because Type 3 summary LSAs are still permitted in a standard stub area (only totally stubby areas block Type 3 LSAs, except the default route). Option E is incorrect because an ASBR inside the area would generate Type 5 LSAs, which are not allowed in a stub area.

Answer

Type 3 summary LSAs are blocked from entering the area

Answer

ASBRs are permitted to reside directly inside the stub area

Question 10

An administrator configures a BGP policy to reject routes with an AS_PATH containing a specific AS number. Which match condition in a Junos routing policy is used to evaluate the AS_PATH?

Accepted Answer

as-path. In Junos, the as-path match condition evaluates routes against a defined as-path regular expression.

Answer

pref

Answer

metric

Answer

community